Linearly extending electrical distribution system having extruded shape conductor rails

ABSTRACT

A linearly extending electrical distribution system for a high speed vehicle driving a current collecting head. At least three conductor rails are provided by longitudinal aligned and spaced apart extruded shapes clamped to transverse C-shaped insulating support members. Expansion joints are provided by connector bars in telescoping relationship with the extruded shapes.

United States Patent [191 Charamel et al. Feb. 5, 1974 [54] LINEARLYEXTENDING ELECTRICAL 3,449,532 6/1969 Dehn 191/29 DISTRIBUTION SYSTEMHAVING 1,080,481 12/1913 Riddle 238/234 2,193,262 3/1940 Wisenor...238/231 EXTRUDED SHAPE CONDUCTOR RAILS 3,345,471 10/1967 Kilburg l9l/23R [75] Inventors: Pierre Charamel, Les Cotes de 503,519 8/1893Bennett.... 191/32 Sassenage; Raymond Brgsson, 1,125,816 l/l9l5 Clarkl9l/44.l Grenoble, both of France [73} Assignee: Merlin Gerin, SocieteAnonyme, Primary Examiner Gerald M Forlenza Grenoble France AssistantExaminer-D. W. Keen [22] Fil d; N 23, 1971 Attorney, Agent, orFirm--Stevens, Davis, Miller &

[21] Appl. No.: 201,510 Mosher [30] Foreign Application Priority DataNov. 30, 1970 France 7043078 Jan. 22, 1971 France 7102907 [57] ABSTRACTMay 11, 1971 France 7117070 A linearly extending electricaldistributionsystem for [52] US. Cl. 191/29, 238/231 a high speed vehicle driving acurrent collecting head. [51] Int. Cl B60m 1/30 At least three conductorrails are provided by longitu- [58] Field of Search... 191/22, 23 R, 29,30, 31, 32, dinal aligned and spaced apart extruded shapes 191/33, 35,40, 44.1; 238/231, 232, 234, clamped to transverse C-shaped insulatingsupport 236, 237; 174/88 B, 99 E, 138 B, 13 members. Expansion jointsare provided by connector bars in telescoping relationship with theextruded [5 6] References Cited shapes. UNITED STATES PATENTS 748,810171904 Taylor .Q 191 23 R 5 Claims, 8 Drawing Figures PATENTEDFEB 5:914I 3.790.725

SHEEY 1 OF 7 ml N o wv Fig.1

PATENTEUFEB 51914 3,790,725 SHEET 6 0F 7 Fig.

PATENTEDFEB 51914, I 3.790.725

SHEU 7 OF 7 LINEARLY EXTENDING ELECTRICAL DISTRIBUTION SYSTEM HAVINGEXTRUDED SHAPE CONDUCTOR RAILS This invention relates to a linearlyextending electrical distribution system having extruded shape conductorrails adapted for sliding contact with a current collecting system.

Distribution systems of this kind have been proposed for use withhigh-speed vehicles, such as air cushion supported vehicles. Suchsystemshave utilized a plurality of, generally three, conductor rails definingbetween them a passageway for a current collecting device comprising anumber of rows of contact shoes, one row for each rail, transmitting thecurrent collected from the rails to the vehicle for on-board uses. Thecontact shoes are resilientlyurged towards the rails and comprise acontact surface mating with the contact surface of therails. The contactshoes are supported from a collector head which is driven by the vehicleand supported in a manner permitting small transverse movements of thevehicle with respect to the collector head, due to irregularities of thetrack or to inertia movements of the vehicle and of the collector headwhich is guided in the passageway by the conductor rails.

It has already been proposed to utilize extruded shape conductor railshaving a high moment of inertia and therigidity of which permits tospace apart the support'members for the rails at relatively longintervals along the track. It is a first object of the invention topermitting rapid assembly of the rail elements and of the expansionjoints.

It is another object of the invention to provide a distribution systemof the kind mentioned having extruded rails ofa one-piece shapeproviding high mechanical. rigidity and still simplerassemblingconditions with regard to the support members.

It'is another object of the invention to provide a low cost distributionsystem having support members for the rails of simple constructionleaving one side of the system free for receiving the support system forthe collector head.

It is a further object of the invention to provide'a distribution systemwhich has expansion joints between aligned sections of conductor railspermitting a rapid and simple assembling of the rails and the jointswithout sacrificing the needed continuity of the contact surfaces ofsuccessive rail portionsin'assemble'd condition.

It is still another object of the invention to provide a distributionsystem wherein the current,supplying-conductorrails are supported in amanner permitting the railsto execute expansion movements in theirsupport These and other objects and advantages will become.

apparent and a fuller understanding of theinvention may be had uponreading of the following description and claims, taken inconjunctionwith the accompanying drawings.

FIG. 1 is an exploded, isometric view of an expansion joint joining theconfronting end portions of a pair of longitudinally aligned'conductorrails according to a first embodiment of the invention.

.provide a rail assembly of an advantageous structure FIG. 2 is aperspective view of a section of a distribution system according toanother embodiment of the invention, with a part of the coveringremoved.

FIG. 3 is an exploded, perspective view at a larger scale of anexpansion joint utilized in conjunction with the embodiment of FIG. 2.

FIG. 4 is an exploded, perspective view of a rigid connection of twosuccessive conductors.

FIG. 5 is a cross-sectional view, at a larger scale of a detail of FIG.2 showing the assembling of a rail to a support member.

FIG. 6 is a plan view of an expansion joint according to a thirdembodiment of the invention;

FIG. 7 is a sectional view on the line 77 of FIG. 6;

FIG. 8 is a sectional view on the line 88 of FIG. 6.

In FIG. 1, a conductor rail is formed of an assembly of longitudinallyaligned and spaced apart metal rail elements 1, 9 consisting of extrudedshapes of light alloy, in particular aluminum, having a base 2 fastenedto support members (not shown) spaced along the rail. The opposite endpart of each rail element is shaped as a convex dihedral front contactsurface 4 and covered by a contact sheet of stainless steel 5. The sidefaces 3 have inner walls defining with the faces 2 and 4 a cavity forthe accomodation of a male end portion 7 of a metal connector bar 8which is adapted to be plugged into the cavity of the end portions ofrail element 1. The connector bar 8 is symmetrical and has an endportion 7'- opposite the end portion 7 and capable of fitting in anadjacent rail element 9 longitudinally aligned with the rail element 1.For reasons of clarity in description, only the joint between the endportion 7 of the connector bar 8 and the rail element 1 will bedescribed in detail, the opposite joint being identical. The male end 7comprises a prismatic part of a cross-section which is complementary tothe cavity 6 in which it fits with soft friction, this cross-sectionbeing square in the example shown in FIG. 1 and taking up only a part ofthe recess of the section 3. The end of therail element 1 is notchedat'10 so as to split the contact surface 4 and permit the insertion of acomplementary part 11 borne by the end 7 of the connector bar 8. Theupper surface of the part 11 is cut in a dihedral shape so as to beflush with the contact surface 4 in inserted position of the connectorbar 8. The contact surface part 11 is extended by an enlarged contactsurface part 12 of solid cross-section which assures the continuity ofthe contact surface between the two spaced apart rail elements 1 and 9.

The lower prismatic extended portion of the ends 7 and 7' of theconnector bar 8 is inserted into a support element 14 of a profilesimilar or identical to that of the slotted end portion of railelement 1. The fastening can be effected in any manner whatsoever, forinstance by screws or rivets, which have beenrepresented schematicallyin FIG. 1 by l-mark s. The support element 14 is preferably fastened toa post (not shown) identical to the support posts for the rail element1, as will be explained hereunder. The connector bar 8 mayadvantageously be of stainless steel so' as to provide a contact surfaceof the same kind along the entire rail.

It is easy to understand that in assembled position of the differentelements of the fail, the support 14 being 2 held fixed, each endvof theelements 1, 9 is capable of carrying out a movement of thermaltranslation which is perfectly guided by the plugged parts 7, 7'. Thecontinuity of the contact surface 4, ll, 12 with which a movable contactshoe (not shown), for instance of copper or of low-carbon-copper alloy,cooperates, is retained practically along the entire rail, a reductionby about one-half of the contact surface occuring solely in theexpansion spaces provided at the connector bar junctions.

In FIGS. 2 to 5, three rail-shaped conductors 15, 16, 17 extend parallelalong a path of displacement of a vehicle (not shown), for instance avehicle which is supported from the ground and propelled by an electric,such as a linear motor. Seen in cross-section, the rails 15, 16, 17 arearranged at the apices of an equilateral triangle and define apassageway or tunnel for a current collecting collector head (not shown)bearing the contact shoes which are urged into contact with the rails to17. The current collecting head is guided in its displacement by therails through the contact shoes in a now well known manner. The rails 15to 17 are borne by transverse support brackets such as 18, 19,distributed along the entire length of the rails 15 to 17. The supportbrackets 18, 19 are preferably entirely of insulating material and attheir base portions by any suitable means a foundation, such as to theballast of the track. They are of generally C shape, the upper arm 20 ofwhich bears two rails 15, 16 extending in a horizontal plane in theexample shown in FIG. 2. The support brackets 18, 19 embraceperipherally on two of its faces the right prism of triangularcross-section defined by the rails 15, 16, 17, leaving free the sideface 22 which gives access to the inner space confined by the rails 15to 17, in particular for the passage of the electrical and mechanicalconnecting members (not shown) of the collector head.

A protective covering of the track is formed of plates or screens 24, 26fastened to the support brackets 18, 19 in such a manner as to surroundthe upper face of the track as well as the side face opposite the freeface 22. The cover 24, 26 makes it possible to avoid accidental contactwith the live conductors 15 to 17 and it protects the latter from theweather and against dirt which might affect a good collecting ofcurrent.

As the extruded shape rails 15 to 17 and the manner of attaching them tothe support brackets 18, 19 are all ofidentical construction, only onerail element 16, will be described in detail, with reference inparticular to FIG. 5. The cross-section of each element of the rail 16has a hollow,more or less rectangular part 28, the front face of whichis shaped as a dihedral 30 constituting the contact surface cooperatingwith the current collecting head. The cavity 32 of the part 28 has arectangular cross-section. The fastening portion of the rail 16comprises two side walls or flanges 34, 36 which are connected to thepart 28. The flanges 34, 36 are spaced apart so as to define a recess 38in the form of a slot opening on to the lower face of the rail 16. Theflanges defining the recess 38 are beveled at 40, 42 for reasons whichwill become clearer from the following.

The arm 20 of the C-shaped support member has a flat bearing surface 44for the base of the flanges 34, 36 of the rail 16, as well as aprojection 46 engaging a recessed portion or groove of the side wall 36.The rail 16 is held by a clamping plate 48 which surrounds the flange 34and is fastened to the arm 20 by screws 50.

.The plate 48 and the bearing surfaces 44, 46 of the support 20constitute a bearing portion clamping the rail 16. The bearing andclamping surfaces of the support member extend parallel to thelongitudinal direction of the rail and it is easy to understand thatonly frictional forces oppose to longitudinal sliding of the railelement with respect to the support 20. The jaws of the clamp 46, 48 mayadvantageously be lined with shoes 52, 54 of synthetic material.

The clamping plate 48 has a resilient portion which is curved in such amanner as to present a slight elasticity which absorbs possibledisalignments or imperfections of the rail and the support members. Themounting is extremely simple and fast, the rail 16 being perfectlypositioned by the bearing surfaces of the support members beforefastening of the clamp 48. The rail element 16 is advantageously ofextruded aluminum, the contact face 30 being covered by a sheet ofstainless steel 56.

Referring now to FIG. 4, there can be noted a manner of rigidlyconnecting two consecutive rail elements 16, 16. A connector bar 58 isinserted in the cavity 38 provided between the flanges 34, 36 of therail element 16, a weld bead 60 being applied at the place provided bythe bevels 40, 42 (see FIG. 5). The presence of the bevels 40, 42facilitates welding in situ avoiding nay machining or preparation of theparts. The connection by welding assures a perfect mechanical andelectrical connection. The remaining protruding part of the connectorbar 58 which is fastened to the rail element 16 fits into thecorresponding cavity of the other rail element 16' to which it can beremovably fastened by bolts 62 or possibly also by welding. The pluggingof the connector bar 58 into the ends of the rail elements 16, 16'assures the alignment of the latter which can be completed, if desired,by the insertion of a guide rod in the upper cavity 32 of the railelements 16, 16'.

The length of a rail, formed of an assembly of various elements 16, 16',may make it indispensable to provide thermal expansion joints at theconfronting ends of subsequent rail elements. Each rail element can berigidly fastened to one of its support members, preferably in thecentral region, the thermal expansion taking place on both sides fromthis fixed point. The standard support brackets 18 can easily beconverted into rigid fastening supports by perforating the clampingplate 48 and the corresponding portion of the rail element so as toprovide a hole for a pin or stud 64 shown in FIG. 5. The stud 64, ofcourse, prevents any longitudinal movement of the rail element withrespect to the corresponding support bracket. In FIG. 2 the supportmember l9 has been shown as a fixed support, two studs 64 passingthrough the clamping plate 48 and the rail element 17.

At each end of a rail element there is provided an expansion joint whichwill be described in further detail with reference to FIG. 3 Theexpansion joint is arranged at the level of a support member 65 to whichthere is rigidly connected a support element 66 of short length having aprofile similar to the rail elements 17 17 and entirely traversed by aconnector bar 68. The part 66 is fastened to the support member 65 bythe standard elements, as shown. The connector bar 68 which is fastenedto the part 66 protrudes on both sides of the latter and has across-section which corresponds to the cavity 32 and to a notch 70provided in the ends of the rail elements 17, 17. In assembled position,the rail elements 17, 17' are plugged with soft friction onto theprojecting ends of the bar 68, the contact surface 72 of the bar 68being flush with the contact surfaces of the rail elements 17, 17 so asto assure continuity of said surface along the rail. It will beunderstood that such a fastening permits only a longitudinal thermaldisplacement, the alignment of the successive rail elements beingperfectly assured. The connector bar 68 is advantageously electricallyshunted by a braid 74 the ends of which are connected to the railelements 17, 17' through a pair of connecting parts 76 which comprise alug inserted into the slot 38 of the elements 17 17' and secured to thelatter by screws 78. The parts 76 have a contact surface 80 on which thecorresponding ends of the braid 74 can be fastened by screws 82. It iseasy to see that the mounting of the expansion joint is effected veryeasily and without any machining in situ. The assembly constitutes atrack of simplified structure and relatively low cost of manufacture. Itis particularly well adapted to the feeding of current to a vehiclemoving at very high speed, for instance at several hundred miles perhour, and supported from the ground.

Referring now to the embodiment shown in FIGS. 6 to 8, a conductor railsupplying current to a current collecting device and which forms a partof a plurality of parallel conductor rails constituting a tunnel orpassageway for the collecting device in a manner analogous to theembodiment shown in FIG. 2, is composed of a plurality of longitudinallyaligned rail elements connected by connector bars at the expansionjoints. FIG. 2 shows such an expansion joint but the rail 100 comprisesa suitable number of rail elements connected by expansion joints, asdesired, all joints being of identical configuration. Each of the twointerconnected rail elements shown in FIG. 6 comprises a pair oftransversely spaced apart extruded metal shapes 101, 103, the upper endsurface of which is bevelled at 102, 104, respectively, to form adihedral front contact face shaped for slidable contact with one or moremovable contact shoes 106 which are biased against the face 102, 104 andwhich are carried by a collector head (not shown).

A plurality of support members 107 consisting of insulator posts areregularly spaced apart along the rail elements to carry the shapes 101,103 through junction-blocs 110 secured to the upper end of the insulatorposts. Each bloc 110 comprises an upper spacing element 112 defining thelateral spacing of the shapes 101, 103 applied thereto. Eachjunction-bloc 110 has a pair of opposite horizontal bearing surfaces 114and 116 supporting the lower flanges 118, 120 of shapes 101, 103,respectively. A pair of lateral clamping members 122, 124 secured toeach junction bloc 110, through bolts 126, 128 respectively, and havingprojections 130, 132 protruding into a longitudinal lateral groove ofshapes 101, 103, respectively, clamp the shapes against the spacingplate 112. Intermediate linings 134, 136 of suitable anti-frictionmaterial, such as polytetrafluorethylene, may be interposed between theprojections 130,132 and the shapes 101, 103 and analogous linings 138,140 between the shapes and the plate 112 to facilitate longitudinalexpansion movements of the rail elements with respect to the stationarysupport members. Of course, the degree of tightening of screws 126, 128should not be excessive to permit said movement. To this end, suitableabutments may be provided. The interfitting of the clamping members andof the junctionbloc with the shapes 101, 103, maintains at all times aperfect alignment of successive rail elements.

FIGS. 6 and 8 show in plan view and in elevational cross-section,respectively, an expansion joint between a pair of longitudinallyaligned and spaced apart rail elements 101, 103. A pair of laterallyspaced apart connector bars 142, consisting of extruded shapes ofconductive material, connect aligned rail elements at each expansionjoint. Each end portion of each shape 103, 101 is cut out at 144, 146,respectively, and the end portions of. the connector bars 142 are alsocut out at 148, in a complementary shape so that the reduced endportions of the rail elements and of the connector bars interfit in aslidable relation permitting longitudinal expansion movements of therail elements 101, 103 with respect to the connector bars 142 wherebythe dihedral front contact surface 102, 104 is continued along theexpansion joint by the connector bars. The transition zones 154 betweenthe rail elements 101 and the corresponding connector bar 142 arelongitudinally staggered with respect to the transition zones 152between the rail elements 103 and the corresponding connector bar 142,as shown in FIG. 6, so that a contact shoe 106 engages the respectivetransition zones successively thereby diminishing the total reduction ofthe contact surface upon running over an expansion joint. The mechanicalguiding of the contact shoe is also improved by this staggering.Preferably the outer end portions of the shapes 101, 103 and of theconnector bars 142 are bevelled, as shown to diminish the overhangsurface of the contact shoe running over gaps 152, 154. In the shownembodiment, the connector bars 142 have a solid intermediate bodyportion defining a contact surface having the same width as that of theshapes 101, 103. As a consequence, a second transition interval 156, 150is produced which is longitudinally offset with respect to the zones154, 152 respectively, causing interfitting end portions of shapes 101,103 and of connector bars 142 to overlap each other. Suitable electricalconnections such as flexible strips 160, 162 interconnect adjacent railelements. Preferably, each connector bar 142 is rigidly fixed to aninsulating support member 164 through a junction-bloc 166 as shown inFIG. 8. lnterfitting end portions of the rail elements 101, 103 and ofthe connector bars 142 have interfitting longitudinally extendingguiding grooves and ribs as at 168, 170 so that the ends of the railelements are perfectly guided in their expansion movements with respectto the stationary connector bars 142 which are rigidly fixed to thestationary support members 164, as stated above. The connector bars 142can of course consist of a single suitable shaped part at each expansionjoint.

What is claimed is:

1. An electrical distribution assembly comprising a conductor rail meansincluding a plurality of longitudinally aligned and spaced apartextruded hollow rail elements having a front contact face adapted forsliding contact engagement with a movable current collecting system anda pair of opposite side faces, a plurality of stationary support membersspaced apart along said conductor rail and having each a bearing portionin clamping relation with said side faces to permit longitudinalexpansion and contraction movements of said rail elements with respectto said support members, said hollow rail elements defining an innercavity extending along the entire length thereof, an extruded connectorbar extending at the meeting end portions of each pair of successiverail elements telescopically a distance into the inner cavity of saidend portions to permit expansion and contraction movements of said railelements one with respect to the other, the end portions of said railelements and of the connector bars having complementary shaped frontcontact faces to provide a continuous front contact surface along theentire length of said conductor rail for slidable contact with saidcurrent collecting system, said assembly further comprising between eachpair of successive rail elements an extruded support element having arecess to accomodate the corresponding connector bar engaging said pairof rail elements telescopically, and means to support each supportelement fixedly from corresponding ones of said stationary supportmembers.

2. An electrical distribution assembly, according to claim 1 wherein thefront contact face of each end portion of each rail element has alongitudinally cut out portion communicating with said cavity, eachconnector bar having a complementary shaped end portion slidably fittinginto said cavity and into said 'cut out portion.

3. An electrical distribution assembly, according to claim 2,whereinsaid support element and the cut out end portion of each railelement have cross sections which are substantially identically shaped.

4. A linearly extending electrical distribution assembly comprising:

three parallel non-coplanar substantially equidistant conductor rails,each conductor rail having a front contact face adapted for slidingcontact engagement with a movable current collecting system, a backface, and a pair of opposite side faces,

a plurality of generally C-shaped support brackets of molded insulatingmaterial extending transversely of said conductor rails and spaced apartalong the length thereof, each support bracket having a base portionsecurable to a foundation and an arm projecting from said base portionand having the free end portion thereof overhanging said base portion,

three bearing portions integrally formed on each support bracket: afirst one adjacent said base portion, a second one at the free end ofsaid arm, and the third one intermediate said first and second ones atthe central portion of said arm, each bearing portion being shaped tocontact and support one of said side faces and said back face of acorresponding one of said conductor rails for the acurate positioningthereof, and

a removable clamp member for each bearing portion secured thereto andengaging the other side face of the corresponding conductor rail toclamp the latter against the bearing portion, in such a manner as topermit longitudinal motion of said conductor rails relative to saidsupport brackets while clamped,

said support brackets embracing said conductor rails in a mannerproviding a passageway for a current collecting support means betweenthe conductor rails supported by said first and second bearing portionsof said support brackets.

5. A linearly extending electrical distribution assembly comprisingthree parallel non-coplanar substantially equidistant conductor rails,each conductor rail including longitudinally aligned metal rail elementshaving a front contact face adapted for sliding contact engagement witha movable current collecting system and a pair of opposite side faces,said assembly further comprising a plurality of insulating supportbrackets extending transversely of said conductor rails and spaced apartalong the length thereof, each support bracket having for each conductorrail a bearing portion in clamping relation with said side faces topermit longitudinal movement of said rail elements relative to saidsupport brackets, said support brackets having a base portion securableto a foundation and an upper arm overhanging said base portion andcarrying at the free end thereof one of said bearing portions so thatsaid brackets embrace said conductor rails incompletely to provide apassageway for a current collecting support means between a pair ofconductor rails along the entire length thereof, wherein each supportbracket comprises a unitary generally C-shaped molded member ofinsulating material having integrally formed thereon three bearingsurfaces to accommodate corresponding portions of said conductor rails,respectively, and three clamp members adapted for clamping said portionsto said surfaces, respectively, each clamp member being removablysecurable to said support bracket, and wherein each said clamp membercomprises a lip member of resilient material shaped for engagement inlongitudinal sliding relation with one of said side faces of said railelements, and bolt means to secure said clamp member to said supportbracket.

3,790,725 February 5, 1974 v Dated Patent No.

lnventol-(s) Pierre CHARAMEL and Raymond BRESSON It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Please rewrite column 8, lines 1 13 as follows:

secured thereto and engaging the other side face of the correspondingconductor rail to clamp the latter against the bearing portion, in sucha manner as to permit longitudinal motion of said conductor railsrelative to said support brackets while clamped,

said support brackets embracing said conductor rails in a mannerproviding a passageway for a current collecting support means betweenthe conductor rails supported by said first and second bearing portionsof said support brackets.

Signed and sealed this 5th day of November 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. Cu MARSHALL DANN Attesting Officer Commissioner ofPatents FORM po'mso USCOMM-DC scan-Poo U, S. GOVERNMENT PRINTING OFFICEI969 0-368-S3

1. An electrical distribution assembly comprising a conductor rail meansincluding a plurality of longitudinally aligned and spaced apartextruded hollow rail elements having a front contact face adapted forsliding contact engagement with a movable current collecting system anda pair of opposite side faces, a plurality of stationary support membersspaced apart along said conductor rail and having each a bearing portionin clamping relation with said side faces to permit longitudinalexpansion and contraction movements of said rail elements with respectto said support members, said hollow rail elements defining an innercavity extending along the entire length thereof, an extruded connectorbar extending at the meeting end portions of each pair of successiverail elements telescopically a distance into the inner cavity of saidend portions to permit expansion and contraction movements of said railelements one with respect to the other, the end portions of said railelements and of the connector bars having complementary shaped frontcontact faces to provide a continuous front contact surface along theentire length of said conductor rail for slidable contact with saidcurrent collecting system, said assembly further comprising between eachpair of successive rail elements an extruded support element having arecess to accomodate the corresponding connector bar engaging said pairof rail elements telescopically, and means to support each supportelement fixedly from corresponding ones of said stationary supportmembers.
 2. An electrical distribution assembly, according to claim 1wherein the front contact face of each end portion of each rail elementhas a longitudinally cut out portion communicating with said cavity,each connector bar having a complementary shaped end portion slidablyfitting into said cavity and into said cut out portion.
 3. An electricaldistribution assembly, according to claim 2, whereinsaid support elementand the cut out end portion of each rail element have cross sectionswhich are substantially identically shaped.
 4. A linearly extendingelectrical distribution assembly comprising: three parallel non-coplanarsubstantially equidistant conductor rails, each conductor rail having afront contact face adapted for sliding contact engagement with a movablecurrent collecting system, a back face, and a pair of opposite sidefaces, a plurality of generally C-shaped support brackets of moldedinsulating material extending transversely of said conductor rails andspaced apart along the length thereof, each support bracket having abase portion securable to a foundation and an aRm projecting from saidbase portion and having the free end portion thereof overhanging saidbase portion, three bearing portions integrally formed on each supportbracket: a first one adjacent said base portion, a second one at thefree end of said arm, and the third one intermediate said first andsecond ones at the central portion of said arm, each bearing portionbeing shaped to contact and support one of said side faces and said backface of a corresponding one of said conductor rails for the acuratepositioning thereof, and a removable clamp member for each bearingportion secured thereto and engaging the other side face of thecorresponding conductor rail to clamp the latter against the bearingportion, in such a manner as to permit longitudinal motion of saidconductor rails relative to said support brackets while clamped, saidsupport brackets embracing said conductor rails in a manner providing apassageway for a current collecting support means between the conductorrails supported by said first and second bearing portions of saidsupport brackets.
 5. A linearly extending electrical distributionassembly comprising three parallel non-coplanar substantiallyequidistant conductor rails, each conductor rail includinglongitudinally aligned metal rail elements having a front contact faceadapted for sliding contact engagement with a movable current collectingsystem and a pair of opposite side faces, said assembly furthercomprising a plurality of insulating support brackets extendingtransversely of said conductor rails and spaced apart along the lengththereof, each support bracket having for each conductor rail a bearingportion in clamping relation with said side faces to permit longitudinalmovement of said rail elements relative to said support brackets, saidsupport brackets having a base portion securable to a foundation and anupper arm overhanging said base portion and carrying at the free endthereof one of said bearing portions so that said brackets embrace saidconductor rails incompletely to provide a passageway for a currentcollecting support means between a pair of conductor rails along theentire length thereof, wherein each support bracket comprises a unitarygenerally C-shaped molded member of insulating material havingintegrally formed thereon three bearing surfaces to accommodatecorresponding portions of said conductor rails, respectively, and threeclamp members adapted for clamping said portions to said surfaces,respectively, each clamp member being removably securable to saidsupport bracket, and wherein each said clamp member comprises a lipmember of resilient material shaped for engagement in longitudinalsliding relation with one of said side faces of said rail elements, andbolt means to secure said clamp member to said support bracket.